The primary objectives of a mass transit access control ticket read-writer system are to: 1) read and record a valid ticket's fare value and information; 2) write altered fare value and other information on the valid ticket; 3) allow quick and convenient entry/exit of persons with a valid ticket, and 4) reject invalid or insufficient fare tickets. Since the patron process may have to handle very large volumes of persons, it also must be fast acting and very reliable. It should also be light weight (to minimize structural support required), easy to maintain, rugged in construction, pleasing in appearance and low in cost. When the read/writer is used in each of the two operating modes (entrance and exit), a minimum of effort to convert from one mode to another mode is also desirable.
Current read/writer devices and methods may accomplish several of these objectives (in one or both of the operating modes) well, but other objectives poorly. A basic type of read/writer system for mass transit applications includes the mechanical transport of the ticket which is entered by the mass transit passenger. The ticket, which includes a magnetic or other encodable strip of material, is carried to a read head. The ticket may be immobilized or transported over the read head at a fixed speed. The read head detects or reads the information stored on the ticket's magnetically encoded tape or strip and the information is transmitted to a microprocessor.
If a valid ticket with sufficient fare is read, the system then encodes new, variable data on the ticket's tape or strip. This variable data typically includes date, location and reduced ticket/fare value. This writing of new variable data is typically validated by a second read head which verifies (read and compare) the new information. Any previous variable data on the ticket is overwritten by the new data. The ticket's encoded tape is typically segregated into fixed data (not normally written over) and variable data (normally written over). Control signals to lock and unlock an access control barrier may be provided via cables from the microprocessor,
The ticket may be used once per passage, if multiple fare or exit control is not required. Remote or supervisory locking/unlocking and ticket return control signals may also be given manually. An example of this type of system is illustrated in U.S. Pat. No. 3,212,615. Versions of this basic type of mechanical transport of a ticket to a read/writer has been implemented in the Washington DC Metro system, the San Francisco BART system, the Singapore and in other mass transit systems.
An alternate type of access system based on a read only system is known conceptually, but has not been applied in this field, in the applicant's knowledge. This type of read only system uses a "swipe" reader, where ticket transport is accomplished manually by the passenger/ticket holder as he/she passes the hand held ticket over a read head or decoder. The ticket may be magnetically or otherwise encoded. If a valid ticket (single use) is detected, access is provided. In a read only system, encoded data is not over written. This basic type of read only system has been implemented in the New York City (New York) and Baltimore (Maryland) mass transit systems. Theoretically, this type of read only system could be applied to a multiple use application, but would require large, sophisticated real time central data processing, tracking and communication systems to each port. No known application of the multiple-use (where the fare value is deducted) read only system concept to mass transit is known to the applicant.
The prior art approaches to ticket read/writing have many limitations, especially when implemented in mass transit applications. The mechanical transport of tickets introduces several elements which are susceptible to failure and unreliable operation. The mechanical transport system can fail, be jammed, mechanically damage the ticket, magnetically alter the data stored on the ticket, may incorrectly place the ticket or allow ticket to move (when it should be immobilized), or may move the ticket across the read head at other than an acceptable speed. This improper ticket placement or movement can cause the reader to incorrectly interpret the stored information and/or allow the writer to erroneously erase fixed data and/or fail to write proper information on the ticket's magnetic strip. Since these failures may occur twice for each trip (entrance and exit modes of operation), and each ticket may be used for multiple trips (advance sale of fares recorded on single ticket) and millions of passengers may be using the mass transit system daily, it can be seen that a very large number of problems can occur, even if the mechanical transport system is statistically reliable (i.e.: experience a small percentage failure rate).
Mechanical systems tend to slow the passage of ticket holding passengers through the access control device. The passenger must locate the ticket entrance slot, determine the proper ticket orientation and edge to be inserted, reorient the ticket if necessary, and insert the proper edge of the ticket into the slot. The mechanical transport system must then grab the ticket and move it to the read/writer head(s). A minimum time of residence over the reader is required to read, process and write data. The ticket then has to be mechanically transported for either return to the passenger or rejected for disposal. In addition to delay, the mechanical passenger ticket transport and handling system interface presents other opportunities for unreliable operation, such as the accidental insertion of materials other than tickets into the ticket slot, contamination of an otherwise valid ticket being transferred to the read head, malfunction of the transport mechanism, multiple simultaneous ticket entry, and the passenger's failure to take a returned ticket.
Even with an ideal user with a contamination free valid ticket, the moving mechanical parts and critical clearances (ticket grabbing, lateral ticket control during read/writer operation, etc.) reduce reliability when compared to a swipe read system. The required added mechanical devices inherent in a mechanical ticket transport also consume more space, mechanical supports and electric power, thus increasing the cost of the access control system.
The multiplicity of elements, unfamiliar users, added processing time, weight and space detract from the objectives of reliability, rapid patron processing and convenient access/exit. As an example, one mass transit system with a mechanical ticket handling type of system experiences approximately 300 failures per day. These failures typically require manual intervention into the access control system, the reissuing of tickets and/or the refunding of fares. In addition to the direct cost of handling these failures and delays, the time required to repair the transport mechanism tends to cause a reduction in ticket sales, increases ticket purchase/delays, and encourages attempts to bypass the malfunctioning ticket/access control systems.
To the best of the applicant's knowledge the swipe writer has not been successfully implemented in the mass transit application. The swipe writers that exist at present can and do corrupt tickets in the operation cycle. This is primarily a result of the difficulty of adequately controlling the location of the ticket during the hand-held write mode of operation. If the magnetic strip is divided into read only (fixed data field) and read/write (variable data field) areas, writing must be precluded from fixed data field. Lateral misslocation of ticket or strip, insufficient time/excessive speed of ticket across read/writer heads, and excessive ticket distance from read/writer head are only some of the causes of possible error. In a mass transit application, passengers are unlikely to consistently and correctly place and retain the ticket over the read/write head. The inherent lack of ticket control and other problems can be expected to result in unacceptable failure rates (failure to properly write and verify writing) for this type of system.
What is needed is a new type of swipe read/writer that is significantly less susceptible to writing and verification errors. This type of system could be used with mechanical or hand held ticket handling systems, but would avoid the many problems and disadvantages of the prior art mechanical ticket read write systems. None of the prior art that the applicant is aware of provides the reliability of the present invention.